Division of Glycoscience, Department of Chemistry, School of Engineering Sciences in Chemistry, Biotechnology and Health, Royal Institute of Technology (KTH), AlbaNova University Centre, SE-106 91 Stockholm, Sweden.
School of Pharmacy, College of Pharmacy, Taipei Medical University, Taipei 110, Taiwan.
Cells. 2021 Feb 27;10(3):510. doi: 10.3390/cells10030510.
(1,3;1,4)-β-D-Glucans, also named as mixed-linkage glucans, are unbranched non-cellulosic polysaccharides containing both (1,3)- and (1,4)-β-linkages. The linkage ratio varies depending upon species origin and has a significant impact on the physicochemical properties of the (1,3;1,4)-β-D-glucans. (1,3;1,4)-β-D-Glucans were thought to be unique in the grasses family (Poaceae); however, evidence has shown that (1,3;1,4)-β-D-glucans are also synthesized in other taxa, including horsetail fern , algae, lichens, and fungi, and more recently, bacteria. The enzyme involved in (1,3;1,4)-β-D-glucan biosynthesis has been well studied in grasses and cereal. However, how this enzyme is able to assemble the two different linkages remains a matter of debate. Additionally, the presence of (1,3;1,4)-β-D-glucan across the species evolutionarily distant from Poaceae but absence in some evolutionarily closely related species suggest that the synthesis is either highly conserved or has arisen twice as a result of convergent evolution. Here, we compare the structure of (1,3;1,4)-β-D-glucans present across various taxonomic groups and provide up-to-date information on how (1,3;1,4)-β-D-glucans are synthesized and their functions.
(1,3;1,4)-β-D-葡聚糖，也称为混合链接葡聚糖，是一种无支链的非纤维素多糖，既含有(1,3)-键，又含有(1,4)-β-键。键合比取决于物种来源，对(1,3;1,4)-β-D-葡聚糖的物理化学性质有重大影响。(1,3;1,4)-β-D-葡聚糖被认为是禾本科植物(Poaceae)家族所特有的；然而，有证据表明，(1,3;1,4)-β-D-葡聚糖也在其他类群中合成，包括马尾草、藻类、地衣和真菌，最近还在细菌中合成。在禾本科植物和谷物中，(1,3;1,4)-β-D-葡聚糖生物合成所涉及的酶已得到很好的研究。然而，这种酶是如何组装这两种不同的键合仍然存在争议。此外，在与禾本科植物进化距离较远的物种中存在(1,3;1,4)-β-D-葡聚糖，但在一些进化上密切相关的物种中却不存在，这表明这种合成要么高度保守，要么由于趋同进化而两次出现。在这里，我们比较了不同分类群中存在的(1,3;1,4)-β-D-葡聚糖的结构，并提供了关于(1,3;1,4)-β-D-葡聚糖是如何合成及其功能的最新信息。
